Review Reports - Long-Term Monitoring of European Brown Hare (<i>Lepus europaeus</i>) Population in the Slovak Danubian Lowland

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper ‘diversity-3123127’ by Vizzarri and co-authors reports the demographic trends of brown hares in Slovakia over the last decades, suggesting the decline of different population dynamics parameters. While this study is very interesting and would contribute to our knowledge of the biology and management of this lagomorph, as well as to support conservation actions (e.g. environmental restoration), the manuscript still suffers several flaws. For example, the statistical methods are not sufficiently explained. The results are also reported quite confusingly. I suggest the author focusing more on and explain better their analytical approach and relevant results. The paper may be accepted after a major, in-depth revision. Below, I provided some general and specific comments, I hope they may help.

General comments

1. Admittedly, I didn’t see how your (L 72-76) ‘analyses aimed to i) identify the environmental variables that influence the distribution of the species’ as you did not provide any data or analysis on the species distribution […] as well as how they ‘iii) highlight any population trend in relation to climate change’, because I did not see any relevant data or analysis (e.g. on precipitation or temperature). Please, I suggest rewriting the aims to better reflect what you actually did in the study.

2. My major comment is related to the use of hunting bag data. The authors state that ‘These offer a good monitoring strategy, as they can be used as a general index of long-term trends, and they can give indications regarding changes in population size and distribution.’ (L 76-78). I may agree on this issue and I’m aware hunting bags have been used to index population trends in hares and other mammals. This approach, however, could be valid especially at coarse scales, and under the assumption the hunting effort is constant both spatially and temporally (otherwise, hunting bags should be standardized by hunting effort, e.g. numbers of hunters, or numbers of km walked during hunts, etc.). The latter issue in particular is critical to obtain robust comparisons while using hunting bags. I understand it would be impossible to account for such hunting effort indices, due to missing data. For this reason, the authors should briefly discuss this issue as a potential limitation of their study. A concise sentence in the Discussion would be sufficient in my opinion.

Specific comments

L42 ‘Population density and hunting bags of…’ would be clearer.

L48 ‘food availability’

L 58 ‘would have resulted…’

L 90 ‘game’ is unclear; please clarify.

L 98 Please, avoid using the term ‘census’ throughout the manuscript; just use ‘count’ instead, which is more correct.

L124-135 There is a high degree of misunderstanding with the terms ‘yearlings’, ‘young’ and ‘juveniles’. Juveniles are defined as newborn offspring (i.e. animals in their first year of life, from 0 to 12 months), whereas yearlings are animals that have been living for at least 1 year (i.e., yearlings are the previous year’s juveniles). (On the other hand, there is no consistent definition for ‘young’, which is a quite general term). Please, adopt the right terminology by updating the text where necessary, and provide the definition of yearlings or juveniles at their first mention, to avoid misunderstanding.

L 140-152 Latin names of all species must go in italics.

L 153-158. Please rewrite the whole section, which is currently unreadable. Mind specifying which statistical test you used and for which variable. Also, as to the ANOVA, it compares a variable (your population parameter I guess) between groups (your 5-year interval I guess), so what does it mean that then ‘performing a linear correlation and regression’? On what/which? (And why, since you used ANOVA?). Also, I see no results of a linear regression, where are there? Please, explain the analysis thoroughly, or the paper cannot be understood.

L 164 Please provide the Latin name of these two ungulate species as this is their first mention in text.

L 169 ‘per year’.

L 196-197 ‘The weight of adult females was significantly higher than that of adult males’.

L 197-199 ‘However this parameter is unsuitable for age estimation, as the maximum recorded weight of a subadult individual was 4.9 kg and the minimum of an adult one was 3.0 kg.’ English needs to be completely checked and revised by a mother-tongue!

L 215-216 ‘Based on individual sex’ (not gender!).

L 231 Do you mean ‘Data regarding’?

L 231-232 (and afterwards) Please avoid writing ‘good value’: this is not scientific writing! The ‘high’ or ‘moderate’ value would sound better.

L 246 ‘Suggesting’ instead of ‘underlining’.

L 304-316 I agree with these reflections on the importance of habitat heterogeneity for hare conservations, as suggested by previous studies. In my opinion, the author should quote the first continental review conducted on the habitat selection in European hares (Mori et. al 2022; DOI: https://doi.org/10.1111/mam.12290), as it clearly demonstrated how this lagomorph selects cropland and grassland while avoiding or using proportionally to the available other habitat types, to better support this statement. That would be better rather than quoting local studies.

L 320 No need to repeat the Latin name as it has already been given.

Table 2. By looking at ‘Corr. Coeff’, I guess if it is the correlation coefficient (Pearson r) between the variable (population parameter) and the 5-year interval number, labelled and ordered as from 1 to 7. Why didn’t you explain such an analytic approach? However, if you want to state that you performed the regression and showed SE, p-value, and correlation coefficient (Pearson r), you should also report the slope i.e. the coefficient of the estimate obtained by the regression analysis. Please, be more clear and explain better.

Comments on the Quality of English Language

English must be edited by a native speaker.

Author Response

RESPONSE LETTER

Authors would like to express a deep thank for valuable reviewers’ reports and Academic Editor’s comment, that surely provided suggestions to improve the quality of our manuscript. Beyond the replies to the comments below, the authors point out the correction of a typing error for the email address of one of the authors (Peter Schultz, schultz.peter84@gmail.com, L9 revised manuscript). All corrections in the text are shown in Red font.

Authors thank the Reviewer for the comment and confirm that all suggestions and corrections were well addressed in the revised article.

General comments

Admittedly, I didn’t see how your (L 72-76) ‘analyses aimed to i) identify the environmental variables that influence the distribution of the species’ as you did not provide any data or analysis on the species distribution […] as well as how they ‘iii) highlight any population trend in relation to climate change’, because I did not see any relevant data or analysis (e.g. on precipitation or temperature). Please, I suggest rewriting the aims to better reflect what you actually did in the study.

Authors welcome the Reviewer’s comment and rephrased the aim of the article (L68-69, revised manuscript), then re-organized the presentation of results and added data regarding ambient conditions of monitored area in relation to population dynamic parameters (L195-210, Fig2, revised manuscript).

My major comment is related to the use of hunting bag data. The authors state that ‘These offer a good monitoring strategy, as they can be used as a general index of long-term trends, and they can give indications regarding changes in population size and distribution.’ (L 76-78). I may agree on this issue and I’m aware hunting bags have been used to index population trends in hares and other mammals. This approach, however, could be valid especially at coarse scales, and under the assumption the hunting effort is constant both spatially and temporally (otherwise, hunting bags should be standardized by hunting effort, e.g. numbers of hunters, or numbers of km walked during hunts, etc.). The latter issue in particular is critical to obtain robust comparisons while using hunting bags. I understand it would be impossible to account for such hunting effort indices, due to missing data. For this reason, the authors should briefly discuss this issue as a potential limitation of their study. A concise sentence in the Discussion would be sufficient in my opinion.

Authors deeply welcome and agree with the Reviewer’s comment. Authors added a sentence to Discussion section to explain potential limitation with the use of bag (L229-231, revised manuscript).

Specific comments

L42 ‘Population density and hunting bags of…’ would be clearer.

Modified as required by Reviewer (L36, revised manuscript).

L48 ‘food availability’

Modified as required by Reviewer(L43, revised manuscript).

L 58 ‘would have resulted…’

Modified as required by Reviewer (L53, revised manuscript).

L 90 ‘game’ is unclear; please clarify.

Clarified as required by Reviewer (L86, revised manuscript).

L 98 Please, avoid using the term ‘census’ throughout the manuscript; just use ‘count’ instead, which is more correct.

Modified as required by Reviewer (L101-102, revised manuscript).

Modified as required by Reviewer (L121-138, revised manuscript).

L 140-152 Latin names of all species must go in italics.

Modified as required by Reviewer (L149-155, revised manuscript).

Authors welcome the Reviewer’s comment and rewrote the statistical section to better explain the analytical approach (L162-164, revised manuscript).

L 164 Please provide the Latin name of these two ungulate species as this is their first mention in text.

Clarified as required by Reviewer (L171, revised manuscript).

L 169 ‘per year’.

Modified as required by Reviewer (L177, revised manuscript).

L 196-197 ‘The weight of adult females was significantly higher than that of adult males’.

Modified as required by Reviewer (L214-215, revised manuscript).

Modified as required by Reviewer (L215-217, revised manuscript).

L 215-216 ‘Based on individual sex’ (not gender!).

Modified as required by Reviewer (L237, revised manuscript).

L 231 Do you mean ‘Data regarding’?

Authors confirm that it was a typing error, the right word was “data” (L252, revised manuscript).

L 231-232 (and afterwards) Please avoid writing ‘good value’: this is not scientific writing! The ‘high’ or ‘moderate’ value would sound better.

Modified as required by Reviewer (L252-253, revised manuscript).

L 246 ‘Suggesting’ instead of ‘underlining’.

Modified as required by Reviewer (L267, revised manuscript).

Authors welcome the Reviewer’s comment and added the suggested citation to support the statement (L328-329, revised manuscript).

L 320 No need to repeat the Latin name as it has already been given.

Modified as required by Reviewer.

Authors welcome the Reviewer’s comment and added the “slope” value into the table 2. In addition, Authors welcome the suggestion to label the years’ columns from 1 to 7.

Reviewer 2 Report

Comments and Suggestions for Authors

It should be noted that the authors undertook quite interesting research that may have both applied and practical significance, especially since it concerns a species that is experiencing a decline in numbers in many countries, and one such species is undoubtedly the gray hare. All research on the functioning of the population of this species is valuable because it provides new data on various threats and possible forms of protection of this species.

After reading the manuscript, I have some observations and comments:

Summary

1. In my opinion, the summary is too long, it can be shortened without including the data it contains - population parameters.

Introduction

1. In my opinion, information about employment is not needed, but rather more detailed information about the structure of crops, but this is probably just methodology.

Results

1. Line 204, from Poland there is much more current data regarding population parameters, it may be worth using them, e.g.:

Logistic regression model for determination of the age of brown hare (Lepus europaeus Pall.) based on their body weight

Population parameters of brown hare (Lepus europaeus L.) in regions of the species highest density in Poland

Characteristics of population indicators of brown hare (Lepus europaeus Pall.) obtained during group hunting in the region with the highest density in western part of the Lublin Region in Poland

For example, in Poland, adult females were heavier than males in studies in 2017.

Line 304-316, in the discussion regarding habitats and their impact on hare populations, data from other European countries could also be provided.

Conclusion

Line 325-329, these are assumptions that do not result from the content of the study, and moreover, such settlements are usually characterized by low effectiveness.

Literature

It should be supplemented and updated.

Although all the above-mentioned cases do not significantly reduce the concept of the study itself or the results obtained, the study should be slightly revised and improved.

After editing the work by improving the text and supplementing it or omitting some fragments, I recommend the manuscript for printing and leave the decision in this respect to the Academic Editor.

Author Response

RESPONSE LETTER

Authors welcome the positive comment of Reviewer.

After reading the manuscript, I have some observations and comments:

Summary

In my opinion, the summary is too long, it can be shortened without including the data it contains - population parameters.

Authors shortened the Abstract deleting the description of data on population parameters, as required by Reviewer.

Introduction

In my opinion, information about employment is not needed, but rather more detailed information about the structure of crops, but this is probably just methodology.

Authors welcome the Reviewer’s comment, emphasizing that they found particularly interesting to mention the report of the Statistical Office of Slovak Republic relative to the important effects of the social-economic situation of Slovak employees with the agriculture and hunting activities. In addition, Authors confirm that information about the studied area are reported in the methodology section.

Results

Line 204, from Poland there is much more current data regarding population parameters, it may be worth using them, e.g.:

Logistic regression model for determination of the age of brown hare (Lepus europaeus Pall.) based on their body weight

Population parameters of brown hare (Lepus europaeus L.) in regions of the species highest density in Poland

Characteristics of population indicators of brown hare (Lepus europaeus Pall.) obtained during group hunting in the region with the highest density in western part of the Lublin Region in Poland

For example, in Poland, adult females were heavier than males in studies in 2017.

Line 304-316, in the discussion regarding habitats and their impact on hare populations, data from other European countries could also be provided.

Authors welcome the Reviewer’s comment, and after evaluation of the suggested references, they were integrated into revised manuscript to improve the quality of interpretation of data (L329-331, revised manuscript).

Conclusion

Line 325-329, these are assumptions that do not result from the content of the study, and moreover, such settlements are usually characterized by low effectiveness.

Authors welcome the comment, but they would like to underline that currently this is not an instrument for the protection and repopulation of the territory used in Slovakia. Based on the results of the present study, Authors believe that the practice of “rearing brown hares in captivity for the following release” might be of interest to evaluate in pilot-studies in specific areas. In literature, several studies (Dematteis et al 2003; Meinieri et al 1998) reviwed by Sokos et al (2014) reported that the use of juveniles and their adaptation in large outdoor enclosures can slightly increase survival rates.

Literature

It should be supplemented and updated.

Authors integrated into revised manuscript several new references to improve the quality of interpretation of data.

Although all the above-mentioned cases do not significantly reduce the concept of the study itself or the results obtained, the study should be slightly revised and improved.

After editing the work by improving the text and supplementing it or omitting some fragments, I recommend the manuscript for printing and leave the decision in this respect to the Academic Editor.

Reviewer 3 Report

Comments and Suggestions for Authors

Manuscript ID: diversity-3123127

Title: Long-term monitoring of European brown hare (Lepus europaeus, L.) population in the Slovak Danubian Lowland

Authors: Francesco Vizzarri *, Jaroslav Slamecka, Tomas Sladecek, Rastislav Jurčík, Ľubomír Ondruška, Peter Schults

Review

The aim of the reviewed paper was to evaluate changes in the population size and distribution of the brown hare in Slovak Danubian Lowland in the last decades (1987 - 2023). In particular, authors aimed

1. To identify the environmental variables that influence the distribution of the species,

2. To identify the variations of dynamic’s indices (sex ratio, age structure and productivity) over the years, and

3. To highlight any population trend in relation to climate change.

Comments on the aim:

· please clarify, what you mean by “distribution” as there is not much about distribution of hares in your text.

· Add at least some results on the changes in climate, as now your aim is without data.

As I understand, hypotheses were not tested, as there are no control areas, therefore, methodology should at least mention this.

Figures and tables are easy to understand, though their formatting could be better, e.g., used fonts are not consistent.

I have no comments as for statistical treatment of data.

Beginning of the Conclusions, Lines 318–322 is not based on the results or analysis of published data. In fact, conclusions seem in disjunction with the rest of text, therefore require revision.

The Back Matter is not full.

Other comments:

Line 3: are you sure about Linnaeus? Brown hare - Lepus europaeus Pallas, 1778?

Abstract is way too long (over 400 words)

Line 36: not sustainable in your study site? In the country?

Map of the study site would be helpful

Line 71: delete “any”

Line 99: counting in what way?

Line 149: Medicago sativa, commonly known as alfalfa, is a perennial flowering plant in the legume family Fabaceae. While it is sometimes confused with clovers due to its similar appearance and usage as forage, it belongs to a different genus (Medicago) than true clovers (which belong to the genus Trifolium). Please check tre rest of your plant species.

Lines 188–194 belong to Methods

Line 192: at least some results should be presented, as there was an aim to investigate climate change effect. I propose to introduce a subchapter in Results.

Lines 195–201: can a figure indication distribution of body mass and their overlap be added to the text or Appendix or Supplement? SE is not the best to illustrate variability and overlap of body mass between age groups and sex groups.

Brown hare numbers have been declining in many post-soviet European countries, therefore manuscript presents actual information and will have wide readership.

Presentation, however, is not easy to follow, especially that authors combined Results and Discussion. Even for the non-native speaker language is not the best one, therefore requiring editing or help of the native speaker. E.g., Line 34,

Presentation putting number of the cited source in the beginning of the sentence, e.g., Line 305 “[34] 305 that hares” should be avoided.

Some important references from the other European countries are not cited, e.g.,

Schai-Braun, S. C., Ruf, T., Klansek, E., Arnold, W., & Hackländer, K. (2020). Positive effects of set-asides on European hare (Lepus europaeus) populations: leverets benefit from an enhanced survival rate. Biological Con

Majzinger, I., Farkas, P., & Kusza, S. (2023). Demographic examination of Brown hare (Lepus europaeus) stocks with special reference during birth and survival in Eastern Hungary.

Panek, M. (2018). Habitat factors associated with the decline in brown hare abundance in Poland in the beginning of the 21st century. Ecological Indicators, 85, 915-920.

Comments on the Quality of English Language

Some line numbers listed in the Comments for Authors

Author Response

RESPONSE LETTER

To identify the environmental variables that influence the distribution of the species,
To identify the variations of dynamic’s indices (sex ratio, age structure and productivity) over the years, and
To highlight any population trend in relation to climate change.

Comments on the aim:

please clarify, what you mean by “distribution” as there is not much about distribution of hares in your text.

Authors welcome the Reviewer’s comment and rephrased the sentence regarding the aim for better comprehension (L68-69, revised manuscript).

Add at least some results on the changes in climate, as now your aim is without data.

As I understand, hypotheses were not tested, as there are no control areas, therefore, methodology should at least mention this.

Authors welcome the Reviewer’s comment and added some specification regarding the control area (L 195-210, and Figure 2, revised manuscript).

Figures and tables are easy to understand, though their formatting could be better, e.g., used fonts are not consistent.

Authors welcome the Reviewer’s comment and corrected figures’ fonts.

I have no comments as for statistical treatment of data.

Beginning of the Conclusions, Lines 318–322 is not based on the results or analysis of published data. In fact, conclusions seem in disjunction with the rest of text, therefore require revision.

Authors welcome the Reviewer’s comment and rephrased the Conclusion section (L341-348, revised manuscript).

The Back Matter is not full.

Authors added all necessary information in the Back Matter section (L362-366, revised manuscript).

Other comments:

Line 3: are you sure about Linnaeus? Brown hare - Lepus europaeus Pallas, 1778?

Authors confirm that the citation Lepus europaeus Pallas, 1778 is correct.

Abstract is way too long (over 400 words)

Authors shortened the Abstract, as required by Reviewer.

Line 36: not sustainable in your study site? In the country?

Authors welcome the Reviewer’s comment, specifying that the considerations arising from this study are limited to the area studied (L28-29, revised manuscript).

Map of the study site would be helpful

Authors added a figure (Figure 1 L96, revised manuscript) showing the Slovak geographical studied areas.

Line 71: delete “any”

Authors deleted the word “any” as required by Reviewer.

Line 99: counting in what way?

Authors confirm the method of census as indicated in L102-103 (revised manuscript), counting on whole area of hunting ground, or at the part of it and the subsequent conversion per unit area.

Authors welcome the Reviewer’s comment and after a careful control they moved Medicago sativa into legumes list of seeds (L149-155, revised manuscript).

Lines 188–194 belong to Methods

Authors removed that information from Results section and added it into Material and Methods section as required by Reviewer (L93-95, revised manuscript).

Line 192: at least some results should be presented, as there was an aim to investigate climate change effect. I propose to introduce a subchapter in Results.

Authors welcome the Reviewer’s comment and added data regarding precipitation and temperature variation during the monitoring period (L195-210, Fig2, revised manuscript).

Authors prefer to present data regarding body weights using a table to get a precise insight into the value, since this is the most used way to preset those data. Regarding the SE value, Authors confirm that the values reported in Table 1 represent the “standard deviation” and not the SE. There was a typing error during the editing of the table. Authors thank the Reviewer for the remark.

Brown hare numbers have been declining in many post-soviet European countries, therefore manuscript presents actual information and will have wide readership.

Authors revised the entire manuscript for the English language editing, improving the readability of the article.

Presentation putting number of the cited source in the beginning of the sentence, e.g., Line 305 “[34] 305 that hares” should be avoided.

Authors corrected the sentence as required by Reviewer.

Some important references from the other European countries are not cited, e.g.,

Majzinger, I., Farkas, P., & Kusza, S. (2023). Demographic examination of Brown hare (Lepus europaeus) stocks with special reference during birth and survival in Eastern Hungary.

Panek, M. (2018). Habitat factors associated with the decline in brown hare abundance in Poland in the beginning of the 21st century. Ecological Indicators, 85, 915-920.

Authors welcome the Reviewer’s comment and added one of the suggested citation (L331, revised manuscript).

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors did a good job in revisiting their manuscript, which has now been improved and can be accepted pending minor revisions. Please make an effort to clarify statistical methods.

L 164. Please list these examined variables (I mean, population parameters against...what?). From Table 1, we do see only a P-value and slope coefficient across years, but also we do see significant comparisons between time intervals (indicated by superscript letters when significant). Therefore we cannot understand whether you performed a regression for each variable (for example N in Table 1 was regressed against the time interval, i.e. 1, 2, 3 etc) or otherwise you performed an ANOVA to test difference between groups (time intervals), so 1 vs 2, 1 vs 3, etc. This needs to be clarified here in Methods, and also in Table 1.

L 214-215. Please acknowledge that additional data is required to test statistical significance between adult males and females in weight, as p=0.049 is really borderline!

L 229-231. This should be partially re-written, and I am not sure the authors have understood my previous comment on this issue, on which I spent a lot commenting on! The problem is not "the effort of hunters to provide data constantly"... The problem is to account for variable hunting effort across space and time so that each hunting bag is standardised by the hunting effort. Without assuming that hunting effort is the same (whatever measure of hunting effort is used, e.g. number of hunters, number of hunting events, etc), hunting bags cannot be considered as proxies of population density. The significance of this latter sentence must be included in the revised version.

L 234 (also at line 249-250 and elsewhere in the manuscript). A 'statistically'....what? Do you mean statistically significant? (But P=0.05 is not significant, P<0.05 is!).

L252 Why is '(P<0.05)' after 'ranged'? It is unclear and misleading. Please correct.

L259 (also L 261 etc). As already said, please avoid using 'good value...' and 'very good value' as that is not scientific writing.

Table 1. Please clarify in the caption to which test is referred the P-value (i.e., regression, correlation, ANOVA etc). Then, please include a title row named 'Time interval' or something similar above the first row with period numbers (1, 2, 3, etc).

L 283. "Different letters on the same row mean statistical difference for P<0.05" Statistical differences between WHAT? Each time interval against each other? Please clarify here and in methods.

Comments on the Quality of English Language

None

Author Response

The authors did a good job in revisiting their manuscript, which has now been improved and can be accepted pending minor revisions. Please make an effort to clarify statistical methods.

Authors thank the Reviewer for the positive comment on revised-article. All additional comments/suggestions were well addressed in the Revised_2 article and they can be found in the text in BLU font.

Authors welcome the Reviewer’s comment and rewrote the statistical section to better explain the used statistical method.

L 214-215. Please acknowledge that additional data is required to test statistical significance between adult males and females in weight, as p=0.049 is really borderline!

Authors reported in Tables 1 the fourth decimal value of p-value to better explain the significance of single item.

Authors confirm that the Reviewer’s comment was highly appreciated and properly understood. Authors re-wrote the sentence to better explain the problematic and the assumption.

L 234 (also at line 249-250 and elsewhere in the manuscript). A 'statistically'....what? Do you mean statistically significant? (But P=0.05 is not significant, P<0.05 is!).

Authors reported in Tables 2 the fourth decimal value of p-value to better explain the significance of single item.

L252 Why is '(P<0.05)' after 'ranged'? It is unclear and misleading. Please correct.

Text has been corrected as required by Reviewer.

L259 (also L 261 etc). As already said, please avoid using 'good value...' and 'very good value' as that is not scientific writing.

Text has been corrected as required by Reviewer.

L 283. "Different letters on the same row mean statistical difference for P<0.05" Statistical differences between WHAT? Each time interval against each other? Please clarify here and in methods.